"We are deploying significant resources … to monitor the airspace around Heathrow and to quickly detect and disrupt any illegal drone activity; some of which are as a result of learning from the incidents at Gatwick," police commander Stuart Cundy said in a statement.

"Our priority is to ensure that there is no ongoing threat to the safety of those at the airport and identify those responsible for this dangerous act.

"I want to be clear that the illegal operation of drones at an airfield is extremely dangerous. Under the Aviation Security Act it is an offence to endanger the safety of an aircraft, anyone found guilty of this offence could face a life sentence."

He said military assistance has been implemented after the sighting but he would not give any further details as it could undermine the effectiveness of the measures.

Transport Minister Chris Grayling had been in contact with the airport concerning the drone sighting.

"The military are preparing to deploy the equipment used at Gatwick at Heathrow quickly should it prove necessary."

In her resignation from politics, Kelly O'Dwyer said she feared another miscarriage in Canberra, far from home. Her announcement is shocking for more than just party-political reasons, writes Emma A. Jane.